Disposable Absorbent Article With Varied Distribution Of Absorbent Particulate Polymer Material And Method of Making Same

ABSTRACT

A disposable absorbent article comprising an absorbent core located in a chassis and comprising absorbent particulate polymer material having a basis weight that varies across the absorbent core. Methods for making such an absorbent core and corresponding disposable absorbent article are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/077,498, filed on Jul. 2, 2008.

FIELD OF THE INVENTION

The present invention generally relates to an absorbent article, andmore particularly to absorbent articles comprising absorbent particulatepolymer material.

BACKGROUND OF THE INVENTION

Absorbent articles, such as disposable diapers, training pants, andadult incontinence undergarments, absorb and contain body exudates. Theyare also intended to prevent body exudates from soiling, wetting, orotherwise contaminating clothing or other articles, such as, bedding,that come in contact with the wearer. A disposable absorbent article,such as a disposal diaper, may be worn for several hours in a dry stateor in a urine loaded state. Accordingly, efforts have been made towardimproving the fit and comfort of the absorbent article to the wearer,both when the article is dry and when the article is fully or partiallyloaded with liquid exudates, while maintaining or enhancing theabsorbing and containing functions of the article.

Disposable absorbent articles, as disposable diapers, are oftenpurchased and used in a relatively large volume. It has been desirableto make disposable absorbent articles with reduced bulk to reduce spaceneeded for transportation, shelf display, and/or storage. Some absorbentarticles, like disposable diapers, have been made thinner by using anabsorbent polymer material (also known as super absorbent polymer), suchas an absorbent particulate polymer material, as the primary liquidabsorbent in the article. Absorbent particulate polymer material absorbsliquid and swells within the article.

A wearer may subject some absorbent articles, such as disposablediapers, to one or more rushes of liquid, such as when urinating. Such awearer typically desires that the absorbent article absorb and hold allsuch liquid during initial and subsequent rushes of liquid. The rate ofabsorbency and capacity of the absorbent particulate polymer materialmay affect the absorbent article's ability to absorb and hold all liquidduring initial and subsequent rushes of liquid. When an absorbentarticle is not able to absorb and hold all liquid, an undesirable liquidleak may occur.

Thus, there remains a desire to enhance the ability of some thin,flexible, and/or inexpensive absorbent articles to absorb and hold oneor more rushes of liquid without substantial leakage of liquid from theabsorbent article.

SUMMARY OF THE INVENTION

The present invention addresses one or more technical problems such asthat described above and provides a disposable absorbent article whichmay comprise a chassis and an absorbent core. The chassis may contain atopsheet and a backsheet. The absorbent core may be located between thetopsheet and the backsheet and an absorbent particulate polymermaterial. The disposable absorbent article comprises an absorbentparticulate polymer material and the absorbent particulate polymermaterial present in the absorbent core has a basis weight that variesacross the absorbent core in a direction substantially perpendicular tothe longitudinal axis of the disposable absorbent article or in adirection substantially parallel to the longitudinal axis of thedisposable absorbent article.

According to another aspect of this invention, a method of making anabsorbent core for use in a disposable absorbent article is providedcomprising depositing an absorbent particulate material on a substrateto form an absorbent core having a longitudinal axis extending form afirst end to a second end such that the absorbent particulate polymermaterial present in the absorbent core has a basis weight that variesacross the absorbent core in a direction substantially perpendicular tothe longitudinal axis or in a direction substantially parallel to thelongitudinal axis.

According to yet another aspect of this invention, a method of making adisposable absorbent article is provided comprising depositing anabsorbent particulate polymer material on a substrate to form anabsorbent core and locating the absorbent core between a topsheet and abacksheet of a chassis. The step of depositing the absorbent particulatepolymer may comprise varying the deposition of the absorbent particulatepolymer such that the absorbent particulate polymer material present inthe absorbent core has a basis weight that varies across the absorbentcore in a direction substantially perpendicular to the longitudinal axisof the disposable absorbent article or in a direction substantiallyparallel to the longitudinal axis of the disposable absorbent article.

Other features and advantages of the invention may be apparent from thefollowing detailed description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a diaper in accordance with an embodiment ofthe present invention.

FIG. 2 is a cross sectional view of the diaper shown in FIG. 1 takenalong the sectional line 2-2 of FIG. 1.

FIG. 3 is a partial cross sectional view of an absorbent core layer inaccordance with an embodiment of this invention wherein more absorbentparticulate polymer material is present toward lateral edges of thediaper than in a central zone of the diaper.

FIG. 4 is a partial cross sectional view of an absorbent core layer inaccordance with another embodiment of this invention.

FIG. 5 is a plan view of the absorbent core layer illustrated in FIG. 3.

FIG. 6 is a plan view of a second absorbent core layer in accordancewith an embodiment of this invention wherein more absorbent particulatepolymer material is present toward lateral edges of the diaper than in acentral zone of the diaper.

FIG. 7 is a partial sectional view of an absorbent core comprising acombination of the first and second absorbent core layers illustrated inFIGS. 5 and 6.

FIG. 8A is a plan view of the absorbent core illustrated in FIG. 7.

FIGS. 8B-8F are plan views of absorbent cores having alternativepatterns of absorbent material.

FIG. 9 is a plan view of the absorbent core in accordance with anembodiment of this invention wherein more absorbent particulate polymermaterial is present toward ends of the diaper than in a central zone ofthe diaper.

FIG. 10 is a plan view of the absorbent core in accordance with anembodiment of this invention wherein more absorbent particulate polymermaterial is present toward lateral edges and ends of the diaper than ina central zone of the diaper.

FIG. 11 is a schematic representation of a rheometer.

FIG. 12 is a schematic illustration of a process for making an absorbentcore in accordance with an embodiment of this invention.

FIG. 13 is a partial sectional view of an apparatus for making anabsorbent core in accordance with an embodiment of this invention.

FIG. 14 is a perspective view of the printing roll illustrated in FIG.13.

FIG. 15 is a partial sectional view of the printing roll illustrated inFIG. 14 showing absorbent particulate polymer material reservoirs.

FIG. 16 is a perspective view of the supporting roll illustrated in FIG.12.

FIG. 17 is a perspective view of a printing roll for making anembodiment of this invention wherein more absorbent particulate polymermaterial is present toward ends of the diaper than in a central zone ofthe diaper.

FIG. 18 is a partial sectional view of the printing roll illustrated inFIG. 17 showing absorbent particulate polymer material reservoirs.

FIG. 19 is a perspective view of a printing roll for making anembodiment of this invention wherein more absorbent particulate polymermaterial is present toward lateral edges and ends of the diaper than ina central zone of the diaper.

DETAILED DESCRIPTION OF THE INVENTION

As summarized above, this invention encompasses a disposable absorbentarticle comprising an absorbent core located in a chassis and comprisingabsorbent particulate polymer material having a basis weight that variesacross the absorbent core. Embodiments of such disposable absorbentarticles are described hereinbelow along with embodiments of apparatusesand methods for making disposable absorbent articles.

Definitions

As used herein, the following terms have the following meanings:

“Absorbent article” refers to devices that absorb and contain bodyexudates, and, more specifically, refers to devices that are placedagainst or in proximity to the body of the wearer to absorb and containthe various exudates discharged from the body. Absorbent articles mayinclude diapers, training pants, adult incontinence undergarments,feminine hygiene products, breast pads, care mats, bibs, wound dressingproducts, and the like. As used herein, the term “body fluids” or “bodyexudates” includes, but is not limited to, urine, blood, vaginaldischarges, breast milk, sweat and fecal matter.

“Absorbent core” means a structure typically disposed between a topsheetand backsheet of an absorbent article for absorbing and containingliquid received by the absorbent article and may comprise one or moresubstrates, absorbent polymer material disposed on the one or moresubstrates, and a thermoplastic composition on the absorbent particulatepolymer material and at least a portion of the one or more substratesfor immobilizing the absorbent particulate polymer material on the oneor more substrates. In a multilayer absorbent core, the absorbent coremay also include a cover layer. The one or more substrates and the coverlayer may comprise a nonwoven. Further, the absorbent core issubstantially cellulose free. The absorbent core does not include anacquisition system, a topsheet, or a backsheet of the absorbent article.In a certain embodiment, the absorbent core would consist essentially ofthe one or more substrates, the absorbent polymer material, thethermoplastic composition, and optionally the cover layer.

“Absorbent polymer material,” “absorbent gelling material,” “AGM,”“superabsorbent,” and “superabsorbent material” are used hereininterchangeably and refer to cross linked polymeric materials that canabsorb at least 5 times their weight of an aqueous 0.9% saline solutionas measured using the Centrifuge Retention Capacity test (Edana441.2-01).

“Absorbent particulate polymer material” is used herein to refer to anabsorbent polymer material which is in particulate form so as to beflowable in the dry state.

“Absorbent particulate polymer material area” as used herein refers tothe area of the core wherein the first substrate 64 and second substrate72 are separated by a multiplicity of superabsorbent particles. In FIG.8A, the boundary of the absorbent particulate polymer material area isdefined by the perimeter of the overlapping circles. There may be someextraneous superabsorbent particles outside of this perimeter betweenthe first substrate 64 and second substrate 72.

“Airfelt” is used herein to refer to comminuted wood pulp, which is aform of cellulosic fiber.

“Comprise,” “comprising,” and “comprises” are open ended terms, eachspecifies the presence of what follows, e.g., a component, but does notpreclude the presence of other features, e.g., elements, steps,components known in the art, or disclosed herein.

“Consisting essentially of” is used herein to limit the scope of subjectmatter, such as that in a claim, to the specified materials or steps andthose that do not materially affect the basic and novel characteristicsof the subject matter.

“Disposable” is used in its ordinary sense to mean an article that isdisposed or discarded after a limited number of usage events overvarying lengths of time, for example, less than about 20 events, lessthan about 10 events, less than about 5 events, or less than about 2events.

“Diaper” refers to an absorbent article generally worn by infants andincontinent persons about the lower torso so as to encircle the waistand legs of the wearer and that is specifically adapted to receive andcontain urinary and fecal waste. As used herein, term “diaper” alsoincludes “pants” which is defined below.

“Fiber” and “filament” are used interchangeably.

A “nonwoven” is a manufactured sheet, web or batt of directionally orrandomly orientated fibers, bonded by friction, and/or cohesion and/oradhesion, excluding paper and products which are woven, knitted, tufted,stitch-bonded incorporating binding yarns or filaments, or felted bywet-milling, whether or not additionally needled. The fibers may be ofnatural or man-made origin and may be staple or continuous filaments orbe formed in situ. Commercially available fibers have diameters rangingfrom less than about 0.001 mm to more than about 0.2 mm and they come inseveral different forms: short fibers (known as staple, or chopped),continuous single fibers (filaments or monofilaments), untwisted bundlesof continuous filaments (tow), and twisted bundles of continuousfilaments (yarn). Nonwoven fabrics can be formed by many processes suchas meltblowing, spunbonding, solvent spinning, electrospinning, andcarding. The basis weight of nonwoven fabrics is usually expressed ingrams per square meter (gsm).

“Pant” or “training pant”, as used herein, refer to disposable garmentshaving a waist opening and leg openings designed for infant or adultwearers. A pant may be placed in position on the wearer by inserting thewearer's legs into the leg openings and sliding the pant into positionabout a wearer's lower torso. A pant may be preformed by any suitabletechnique including, but not limited to, joining together portions ofthe article using refastenable and/or non-refastenable bonds (e.g.,seam, weld, adhesive, cohesive bond, fastener, etc.). A pant may bepreformed anywhere along the circumference of the article (e.g., sidefastened, front waist fastened). While the terms “pant” or “pants” areused herein, pants are also commonly referred to as “closed diapers,”“prefastened diapers,” “pull-on diapers,” “training pants,” and“diaper-pants”. Suitable pants are disclosed in U.S. Pat. No. 5,246,433,issued to Hasse, et al. on Sep. 21, 1993; U.S. Pat. No. 5,569,234,issued to Buell et al. on Oct. 29, 1996; U.S. Pat. No. 6,120,487, issuedto Ashton on Sep. 19, 2000; U.S. Pat. No. 6,120,489, issued to Johnsonet al. on Sep. 19, 2000; U.S. Pat. No. 4,940,464, issued to Van Gompelet al. on Jul. 10, 1990; U.S. Pat. No. 5,092,861, issued to Nomura etal. on Mar. 3, 1992; U.S. Patent Publication No. 2003/0233082 A1,entitled “Highly Flexible And Low Deformation Fastening Device”, filedon Jun. 13, 2002; U.S. Pat. No. 5,897,545, issued to Kline et al. onApr. 27, 1999; U.S. Pat. No. 5,957,908, issued to Kline et al on Sep.28, 1999.

“Substantially cellulose free” is used herein to describe an article,such as an absorbent core, that contains less than 10% by weightcellulosic fibers, less than 5% cellulosic fibers, less than 1%cellulosic fibers, no cellulosic fibers, or no more than an immaterialamount of cellulosic fibers. An immaterial amount of cellulosic materialwould not materially affect the thinness, flexibility, or absorbency ofan absorbent core.

“Substantially continuously distributed” as used herein indicates thatwithin the absorbent particulate polymer material area, the firstsubstrate 64 and second substrate 72 are separated by a multiplicity ofsuperabsorbent particles. It is recognized that there may be minorincidental contact areas between the first substrate 64 and secondsubstrate 72 within the absorbent particulate polymer material area.Incidental contact areas between the first substrate 64 and secondsubstrate 72 may be intentional or unintentional (e.g. manufacturingartifacts) but do not form geometries such as pillows, pockets, tubes,quilted patterns and the like.

“Thermoplastic adhesive material” as used herein is understood tocomprise a polymer composition from which fibers are formed and appliedto the superabsorbent material with the intent to immobilize thesuperabsorbent material in both the dry and wet state. The thermoplasticadhesive material of the present invention forms a fibrous network overthe superabsorbent material.

“Thickness” and “caliper” are used herein interchangeably.

Absorbent Articles

FIG. 1 is a plan view of a diaper 10 according to a certain embodimentof the present invention. The diaper 10 is shown in its flat out,uncontracted state (i.e., without elastic induced contraction) andportions of the diaper 10 are cut away to more clearly show theunderlying structure of the diaper 10. A portion of the diaper 10 thatcontacts a wearer is facing the viewer in FIG. 1. The diaper 10generally may comprise a chassis 12 and an absorbent core 14 disposed inthe chassis.

The chassis 12 of the diaper 10 in FIG. 1 may comprise the main body ofthe diaper 10. The chassis 12 may comprise an outer covering 16including a topsheet 18, which may be liquid pervious, and/or abacksheet 20, which may be liquid impervious. The absorbent core 14 maybe encased between the topsheet 18 and the backsheet 20. The chassis 12may also include side panels 22, elasticized leg cuffs 24, and anelastic waist feature 26.

The leg cuffs 24 and the elastic waist feature 26 may each typicallycomprise elastic members 28. One end portion of the diaper 10 may beconfigured as a first waist region 30 of the diaper 10. An opposite endportion of the diaper 10 may be configured as a second waist region 32of the diaper 10. An intermediate portion of the diaper 10 may beconfigured as a crotch region 34, which extends longitudinally betweenthe first and second waist regions 30 and 32. The waist regions 30 and32 may include elastic elements such that they gather about the waist ofthe wearer to provide improved fit and containment (elastic waistfeature 26). The crotch region 34 is that portion of the diaper 10which, when the diaper 10 is worn, is generally positioned between thewearer's legs.

The diaper 10 is depicted in FIG. 1 with its longitudinal axis 36 andits transverse axis 38. The periphery 40 of the diaper 10 is defined bythe outer edges of the diaper 10 in which the longitudinal edges 42 rungenerally parallel to the longitudinal axis 36 of the diaper 10 and theend edges 44 run between the longitudinal edges 42 generally parallel tothe transverse axis 38 of the diaper 10. The chassis 12 may alsocomprise a fastening system, which may include at least one fasteningmember 46 and at least one stored landing zone 48.

The diaper 10 may also include such other features as are known in theart including front and rear ear panels, waist cap features, elasticsand the like to provide better fit, containment and aestheticcharacteristics. Such additional features are well known in the art andare e.g., described in U.S. Pat. No. 3,860,003 and U.S. Pat. No.5,151,092.

In order to keep the diaper 10 in place about the wearer, at least aportion of the first waist region 30 may be attached by the fasteningmember 46 to at least a portion of the second waist region 32 to formleg opening(s) and an article waist. When fastened, the fastening systemcarries a tensile load around the article waist. The fastening systemmay allow an article user to hold one element of the fastening system,such as the fastening member 46, and connect the first waist region 30to the second waist region 32 in at least two places. This may beachieved through manipulation of bond strengths between the fasteningdevice elements.

According to certain embodiments, the diaper 10 may be provided with are-closable fastening system or may alternatively be provided in theform of a pant-type diaper. When the absorbent article is a diaper, itmay comprise a re-closable fastening system joined to the chassis forsecuring the diaper to a wearer. When the absorbent article is apant-type diaper, the article may comprise at least two side panelsjoined to the chassis and to each other to form a pant. The fasteningsystem and any component thereof may include any material suitable forsuch a use, including but not limited to plastics, films, foams,nonwoven, woven, paper, laminates, fiber reinforced plastics and thelike, or combinations thereof. In certain embodiments, the materialsmaking up the fastening device may be flexible. The flexibility mayallow the fastening system to conform to the shape of the body and thus,reduce the likelihood that the fastening system will irritate or injurethe wearer's skin.

For unitary absorbent articles, the chassis 12 and absorbent core 14 mayform the main structure of the diaper 10 with other features added toform the composite diaper structure. While the topsheet 18, thebacksheet 20, and the absorbent core 14 may be assembled in a variety ofwell-known configurations, preferred diaper configurations are describedgenerally in U.S. Pat. No. 5,554,145 entitled “Absorbent Article WithMultiple Zone Structural Elastic-Like Film Web Extensible Waist Feature”issued to Roe et al. on Sep. 10, 1996; U.S. Pat. No. 5,569,234 entitled“Disposable Pull-On Pant” issued to Buell et al. on Oct. 29, 1996; andU.S. Pat. No. 6,004,306 entitled “Absorbent Article WithMulti-Directional Extensible Side Panels” issued to Robles et al. onDec. 21, 1999.

The topsheet 18 in FIG. 1 may be fully or partially elasticized or maybe foreshortened to provide a void space between the topsheet 18 and theabsorbent core 14. Exemplary structures including elasticized orforeshortened topsheets are described in more detail in U.S. Pat. No.5,037,416 entitled “Disposable Absorbent Article Having ElasticallyExtensible Topsheet” issued to Allen et al. on Aug. 6, 1991; and U.S.Pat. No. 5,269,775 entitled “Trisection Topsheets for DisposableAbsorbent Articles and Disposable Absorbent Articles Having SuchTrisection Topsheets” issued to Freeland et al. on Dec. 14, 1993.

The backsheet 26 may be joined with the topsheet 18. The backsheet 20may prevent the exudates absorbed by the absorbent core 14 and containedwithin the diaper 10 from soiling other external articles that maycontact the diaper 10, such as bed sheets and undergarments. In certainembodiments, the backsheet 26 may be substantially impervious to liquids(e.g., urine) and comprise a laminate of a nonwoven and a thin plasticfilm such as a thermoplastic film having a thickness of about 0.012 mm(0.5 mil) to about 0.051 mm (2.0 mils). Suitable backsheet films includethose manufactured by Tredegar Industries Inc. of Terre Haute, Ind. andsold under the trade names X15306, X10962, and X10964. Other suitablebacksheet materials may include breathable materials that permit vaporsto escape from the diaper 10 while still preventing liquid exudates frompassing through the backsheet 10. Exemplary breathable materials mayinclude materials such as woven webs, nonwoven webs, composite materialssuch as film-coated nonwoven webs, and microporous films such asmanufactured by Mitsui Toatsu Co., of Japan under the designation ESPOIRNO and by EXXON Chemical Co., of Bay City, Tex., under the designationEXXAIRE. Suitable breathable composite materials comprising polymerblends are available from Clopay Corporation, Cincinnati, Ohio under thename HYTREL blend P18-3097. Such breathable composite materials aredescribed in greater detail in PCT Application No. WO 95/16746,published on Jun. 22, 1995 in the name of E. I. DuPont. Other breathablebacksheets including nonwoven webs and apertured formed films aredescribed in U.S. Pat. No. 5,571,096 issued to Dobrin et al. on Nov. 5,1996.

In certain embodiments, the backsheet of the present invention may havea water vapor transmission rate (WVTR) of greater than about 2000 g/24h/m², greater than about 3000 g/24 h/m², greater than about 5000 g/24h/m², greater than about 6000 g/24 h/m², greater than about 7000 g/24h/m², greater than about 8000 g/24 h/m², greater than about 9000 g/24h/m², greater than about 10000 g/24 h/m², greater than about 11000 g/24h/m², greater than about 12000 g/24 h/m², greater than about 15000 g/24h/m², measured according to WSP 70.5 (08) at 37.8° C. and 60% RelativeHumidity.

FIG. 2 shows a cross section of FIG. 1 taken along the sectional line2-2 of FIG. 1. Starting from the wearer facing side, the diaper 10 maycomprise the topsheet 18, the components of the absorbent core 14, andthe backsheet 20. According to a certain embodiment, diaper 10 may alsocomprise an acquisition system 50 disposed between the liquid permeabletopsheet 18 and a wearer facing side of the absorbent core 14. Theacquisition system 50 may be in direct contact with the absorbent core.The acquisition system 50 may comprise a single layer or multiplelayers, such as an upper acquisition layer 52 facing towards thewearer's skin and a lower acquisition 54 layer facing the garment of thewearer. According to a certain embodiment, the acquisition system 50 mayfunction to receive a surge of liquid, such as a gush of urine. In otherwords, the acquisition system 50 may serve as a temporary reservoir forliquid until the absorbent core 14 can absorb the liquid.

In a certain embodiment, the acquisition system 50 may comprisechemically cross-linked cellulosic fibers. Such cross-linked cellulosicfibers may have desirable absorbency properties. Exemplary chemicallycross-linked cellulosic fibers are disclosed in U.S. Pat. No. 5,137,537.In certain embodiments, the chemically cross-linked cellulosic fibersare cross-linked with between about 0.5 mole % and about 10.0 mole % ofa C₂ to C₉ polycarboxylic cross-linking agent or between about 1.5 mole% and about 6.0 mole % of a C₂ to C₉ polycarboxylic cross-linking agentbased on glucose unit. Citric acid is an exemplary cross-linking agent.In other embodiments, polyacrylic acids may be used. Further, accordingto certain embodiments, the cross-linked cellulosic fibers have a waterretention value of about 25 to about 60, or about 28 to about 50, orabout 30 to about 45. A method for determining water retention value isdisclosed in U.S. Pat. No. 5,137,537. According to certain embodiments,the cross-linked cellulosic fibers may be crimped, twisted, or curled,or a combination thereof including crimped, twisted, and curled.

In a certain embodiment, one or both of the upper and lower acquisitionlayers 52 and 54 may comprise a non-woven, which may be hydrophilic.Further, according to a certain embodiment, one or both of the upper andlower acquisition layers 52 and 54 may comprise the chemicallycross-linked cellulosic fibers, which may or may not form part of anonwoven material. According to an exemplary embodiment, the upperacquisition layer 52 may comprise a nonwoven, without the cross-linkedcellulosic fibers, and the lower acquisition layer 54 may comprise thechemically cross-linked cellulosic fibers. Further, according to anembodiment, the lower acquisition layer 54 may comprise the chemicallycross-linked cellulosic fibers mixed with other fibers such as naturalor synthetic polymeric fibers. According to exemplary embodiments, suchother natural or synthetic polymeric fibers may include high surfacearea fibers, thermoplastic binding fibers, polyethylene fibers,polypropylene fibers, PET fibers, rayon fibers, lyocell fibers, andmixtures thereof. According to a particular embodiment, the loweracquisition layer 54 has a total dry weight, the cross-linked cellulosicfibers are present on a dry weight basis in the upper acquisition layerin an amount from about 30% to about 95% by weight of the loweracquisition layer 54, and the other natural or synthetic polymericfibers are present on a dry weight basis in the lower acquisition layer54 in an amount from about 70% to about 5% by weight of the loweracquisition layer 54. According to another embodiment, the cross-linkedcellulosic fibers are present on a dry weight basis in the firstacquisition layer in an amount from about 80% to about 90% by weight ofthe lower acquisition layer 54, and the other natural or syntheticpolymeric fibers are present on a dry weight basis in the loweracquisition layer 54 in an amount from about 20% to about 10% by weightof the lower acquisition layer 54.

According to a certain embodiment, the lower acquisition layer 54desirably has a high fluid uptake capability. Fluid uptake is measuredin grams of absorbed fluid per gram of absorbent material and isexpressed by the value of “maximum uptake.” A high fluid uptakecorresponds therefore to a high capacity of the material and isbeneficial, because it ensures the complete acquisition of fluids to beabsorbed by an acquisition material. According to exemplary embodiments,the lower acquisition layer 54 has a maximum uptake of about 10 g/g.

A relevant attribute of the upper acquisition layer 54 is its MedianDesorption Pressure, MDP. The MDP is a measure of the capillary pressurethat is required to dewater the lower acquisition layer 54 to about 50%of its capacity at 0 cm capillary suction height under an appliedmechanical pressure of 0.3 psi. Generally, a relatively lower MDP may beuseful. The lower MDP may allow the lower acquisition layer 54 to moreefficiently drain the upper acquisition material. Without wishing to bebound by theory, a given distribution material may have a definablecapillary suction. The ability of the lower acquisition layer 54 to moveliquid vertically via capillary forces will be directly impacted bygravity and the opposing capillary forces associated with desorption ofthe upper acquisition layer. Minimizing these capillary forces maypositively impact the performance of the lower acquisition layer 54.However, in a certain embodiment the lower acquisition layer 54 may alsohave adequate capillary absorption suction in order to drain the layersabove (upper acquisition layer 52 and topsheet 18, in particular) and totemporarily hold liquid until the liquid can be partitioned away by theabsorbent core components. Therefore, in a certain embodiment, the loweracquisition layer 54 may have a minimum MDP of greater than 5 cm.Further, according to exemplary embodiments, the lower acquisition layer54 has an MDP value of less than about 20.5 cm H₂O, or less than about19 cm H₂O, or less than about 18 cm H₂O to provide for fast acquisition.

The methods for determining MDP and maximum uptake are disclosed in U.S.patent application Ser. No. 11/600,691 (Flohr et al.). For example,according to a first embodiment, the lower acquisition layer 54 maycomprise about 70% by weight of chemically cross-linked cellulosefibers, about 10% by weight polyester (PET), and about 20% by weightuntreated pulp fibers. According to a second embodiment, the loweracquisition layer 54 may comprise about 70% by weight chemicallycross-linked cellulose fibers, about 20% by weight lyocell fibers, andabout 10% by weight PET fibers. According to a third embodiment, thelower acquisition layer 54 may comprise about 68% by weight chemicallycross-linked cellulose fibers, about 16% by weight untreated pulpfibers, and about 16% by weight PET fibers. In one embodiment, the loweracquisition layer 54 may comprise from about 90-100% by weightchemically cross-linked cellulose fibers.

Suitable non-woven materials for the upper and lower acquisition layers52 and 54 include, but are not limited to SMS material, comprising aspunbonded, a melt-blown and a further spunbonded layer. In certainembodiments, permanently hydrophilic non-wovens, and in particular,nonwovens with durably hydrophilic coatings are desirable. Anothersuitable embodiment comprises a SMMS-structure. In certain embodiments,the non-wovens are porous.

In certain embodiments, suitable non-woven materials may include, butare not limited to synthetic fibers, such as PE, PET, and PP. Aspolymers used for nonwoven production may be inherently hydrophobic,they may be coated with hydrophilic coatings. One way to producenonwovens with durably hydrophilic coatings, is via applying ahydrophilic monomer and a radical polymerization initiator onto thenonwoven, and conducting a polymerization activated via UV lightresulting in monomer chemically bound to the surface of the nonwoven asdescribed in co-pending U.S. Patent Publication No. 2005/0159720.Another way to produce nonwovens with durably hydrophilic coatings is tocoat the nonwoven with hydrophilic nanoparticles as described inco-pending applications U.S. Pat. No. 7,112,621 to Rohrbaugh et al. andin PCT Application Publication WO 02/064877.

Typically, nanoparticles have a largest dimension of below 750 nm.Nanoparticles with sizes ranging from 2 to 750 nm may be economicallyproduced. An advantage of nanoparticles is that many of them can beeasily dispersed in water solution to enable coating application ontothe nonwoven, they typically form transparent coatings, and the coatingsapplied from water solutions are typically sufficiently durable toexposure to water. Nanoparticles can be organic or inorganic, syntheticor natural. Inorganic nanoparticles generally exist as oxides,silicates, and/or, carbonates. Typical examples of suitablenanoparticles are layered clay minerals (e.g., LAPONITE™ from SouthernClay Products, Inc. (USA), and Boehmite alumina (e.g., Disperal P2™ fromNorth American Sasol. Inc.). According to a certain embodiment, asuitable nanoparticle coated non-woven is that disclosed in theco-pending patent application Ser. No. 10/758,066 entitled “Disposableabsorbent article comprising a durable hydrophilic core wrap” toEkaterina Anatolyevna Ponomarenko and Mattias NMN Schmidt.

Further useful non-wovens are described in U.S. Pat. No. 6,645,569 toCramer et al., U.S. Pat. No. 6,863,933 to Cramer et al., U.S. Pat. No.7,112,621 to Rohrbaugh et al., and co-pending patent application Ser.No. 10/338,603 to Cramer et al. and Ser. No. 10/338,610 to Cramer et al.

In some cases, the nonwoven surface can be pre-treated with high energytreatment (corona, plasma) prior to application of nanoparticlecoatings. High energy pre-treatment typically temporarily increases thesurface energy of a low surface energy surface (such as PP) and thusenables better wetting of a nonwoven by the nanoparticle dispersion inwater.

Notably, permanently hydrophilic non-wovens are also useful in otherparts of an absorbent article. For example, topsheets and absorbent corelayers comprising permanently hydrophilic non-wovens as described abovehave been found to work well.

According to a certain embodiment, the upper acquisition layer 52 maycomprise a material that provides good recovery when external pressureis applied and removed. Further, according to a certain embodiment, theupper acquisition layer 52 may comprise a blend of different fibersselected, for example from the types of polymeric fibers describedabove. In some embodiments, at least a portion of the fibers may exhibita spiral-crimp which has a helical shape. In some embodiments, the upperacquisition layer 52 may comprise fibers having different degrees ortypes of crimping, or both. For example, one embodiment may include amixture of fibers having about 8 to about 12 crimps per inch (cpi) orabout 9 to about 10 cpi, and other fibers having about 4 to about 8 cpior about 5 to about 7 cpi. Different types of crimps include, but arenot limited to a 2D crimp or “flat crimp” and a 3D or spiral-crimp.According to a certain embodiment, the fibers may include bi-componentfibers, which are individual fibers each comprising different materials,usually a first and a second polymeric material. It is believed that theuse of side-by-side bi-component fibers is beneficial for imparting aspiral-crimp to the fibers.

The upper acquisition layer 52 may be stabilized by a latex binder, forexample a styrene-butadiene latex binder (SB latex), in a certainembodiment. Processes for obtaining such lattices are known, forexample, from EP 149 880 (Kwok) and US 2003/0105190 (Diehl et al.). Incertain embodiments, the binder may be present in the upper acquisitionlayer 52 in excess of about 12%, about 14% or about 16% by weight. Forcertain embodiments, SB latex is available under the trade name GENFLO™3160 (OMNOVA Solutions Inc.; Akron, Ohio).

The absorbent core 14 in FIGS. 1-8A generally is disposed between thetopsheet 18 and the backsheet 20 and comprises two layers, a firstabsorbent layer 60 and a second absorbent layer 62. As best shown inFIG. 3, the first absorbent layer 60 of the absorbent core 14 comprisesa substrate 64, an absorbent particular polymer material 66 on thesubstrate 64, and a thermoplastic composition 68 on the absorbentparticulate polymer material 66 and at least portions of the firstsubstrate 64 as an adhesive for covering and immobilizing the absorbentparticulate polymer material 66 on the first substrate 64. According toanother embodiment illustrated in FIG. 4, the first absorbent layer 60of the absorbent core 14 may also include a cover layer 70 on thethermoplastic composition 68. The absorbent core 14 may also includeanother layer 69 of thermoplastic composition on the first substrate 64for anchoring the absorbent particulate polymer material 66 to the firstsubstrate 64.

Likewise, as best illustrated in FIG. 2, the second absorbent layer 62of the absorbent core 14 may also include a substrate 72, athermoplastic composition 73 on the substrate, an absorbent particulatepolymer material 74 adhered to the second substrate 72 with thethermoplastic composition, and a thermoplastic composition 66 on theabsorbent particulate polymer material 74 and at least a portion of thesecond substrate 72 or first layer of thermoplastic composition forimmobilizing the absorbent particulate polymer material 74 on the secondsubstrate 72. Although not illustrated, the second absorbent layer 62may also include a cover layer such as the cover layer 70 illustrated inFIG. 4.

The substrate 64 of the first absorbent layer 60 may be referred to as adusting layer and has a first surface 78 which faces the backsheet 20 ofthe diaper 10 and a second surface 80 which faces the absorbentparticulate polymer material 66. Likewise, the substrate 72 of thesecond absorbent layer 62 may be referred to as a core cover and has afirst surface 82 facing the topsheet 18 of the diaper 10 and a secondsurface 84 facing the absorbent particulate polymer material 74. Thefirst and second substrates 64 and 72 may be adhered to one another withadhesive about the periphery to form an envelope about the absorbentparticulate polymer materials 66 and 74 to hold the absorbentparticulate polymer material 66 and 74 within the absorbent core 14.

According to a certain embodiment, the substrates 64 and 72 of the firstand second absorbent layers 60 and 62 may be a non-woven material, suchas those nonwoven materials described above. In certain embodiments, thenon-wovens are porous and in one embodiment has a pore size of about 32microns.

As illustrated in FIGS. 1-8A, the absorbent particulate polymer material66 and 74 is deposited on the respective substrates 64 and 72 of thefirst and second absorbent layers 60 and 62 in small and large clusters90 and 91 of particles to form a grid pattern 92 comprising land areas94 and junction areas 96 between the land areas 94. As defined herein,land areas 94 are areas where the thermoplastic adhesive material doesnot contact the nonwoven substrate or the auxiliary adhesive directly;junction areas 96 are areas where the thermoplastic adhesive materialdoes contact the nonwoven substrate or the auxiliary adhesive directly.The junction areas 96 in the grid pattern 92 contain little or noabsorbent particulate polymer material 66 and 74. The land areas 94 andjunction areas 96 can have a variety of shapes including, but notlimited to, circular, oval, square, rectangular, triangular, and thelike.

The grid pattern shown in FIG. 8A is a square grid with regular spacingand size of the land areas. Other grid patterns including hexagonal,rhombic, orthorhombic, parallelogram, triangular, rectangular, andcombinations thereof may also be used. The spacing between the gridlines may be regular or irregular.

The size of the land areas 94 in the grid patterns 92 may vary.According to certain embodiments, the width 119 of the land areas 94 inthe grid patterns 92 ranges from about 8 mm to about 12 mm. In a certainembodiment, the width of the land areas 94 is about 10 mm. The junctionareas 96, on the other hand, in certain embodiments, have a width orlarger span of less than about 5 mm, less than about 3 mm, less thanabout 2 mm, less than about 1.5 mm, less than about 1 mm, or less thanabout 0.5 mm.

The small clusters 90 of absorbent particulate polymer material 66 and74 are thinner than the large clusters 91 of absorbent particulatepolymer material 66 and 74 and impart a lower basis weight of absorbentparticulate polymer material 66 and 74 to the area of the absorbent core14 in which the small clusters 90 are located. Likewise, the largeclusters 91 of absorbent particulate polymer material 66 and 74 arethicker than the small clusters 90 of absorbent particulate polymermaterial 66 and 74 and impart a higher basis weight of absorbentparticulate polymer material 66 and 74 to the area of the absorbent core14 in which the large clusters 91 are located. This creates a variedprofile of absorbent particulate polymer material across the absorbentcore 14.

As shown in FIG. 8A, the absorbent core 14 has a longitudinal axis 100extending from a rear end 102 to a front end 104 and a transverse axis106 perpendicular to the longitudinal axis 100 extending from a firstedge 108 to a second edge 110. The grid pattern 92 of absorbentparticulate polymer material clusters 90 and 91 is arranged on thesubstrates 64 and 72 of the respective absorbent layers 60 and 62 suchthat the grid pattern 92 formed by the arrangement of land areas 94 andjunction areas 96 forms a pattern angle 112. The pattern angle 112 maybe greater than 0, or 15 to 30 degrees, or from about 5 to about 85degrees, or from about 10 to about 60 degrees, or from about 15 to about30 degrees from the longitudinal axis 100 of the absorbent core 14.

As best seen in FIGS. 7 and 8A, the first and second layers 60 and 62may be combined to form the absorbent core 14. The absorbent core 14 hasan absorbent particulate polymer material area 114 bounded by a patternlength 116 and a pattern width 118. The extent and shape of theabsorbent particulate polymer material area 114 may vary depending onthe desired application of the absorbent core 14 and the particularabsorbent article in which it may be incorporated. In a certainembodiment, however, the absorbent particulate polymer material area 114extends substantially entirely across the absorbent core 14, such as isillustrated in FIG. 8A.

The first and second absorbent layers 60 and 62 may be combined togetherto form the absorbent core 14 such that the grid patterns 92 of therespective first and second absorbent layers 62 and 64 are offset fromone another along the length and/or width of the absorbent core 14. Therespective grid patterns 92 may be offset such that the absorbentparticulate polymer material 66 and 74 is substantially continuouslydistributed across the absorbent particulate polymer area 114. In acertain embodiment, absorbent particulate polymer material 66 and 74 issubstantially continuously distributed across the absorbent particulatepolymer material area 114 despite the individual grid patterns 92comprising absorbent particulate polymer material 66 and 74discontinuously distributed across the first and second substrates 64and 72 in clusters 90 and 91. In a certain embodiment, the grid patternsmay be offset such that the land areas 94 of the first absorbent layer60 face the junction areas 96 of the second absorbent layer 62 and theland areas of the second absorbent layer 62 face the junction areas 96of the first absorbent layer 60. When the land areas 94 and junctionareas 96 are appropriately sized and arranged, the resulting combinationof absorbent particulate polymer material 66 and 74 is a substantiallycontinuous layer of absorbent particular polymer material across theabsorbent particulate polymer material area 114 of the absorbent core 14(i.e. first and second substrates 64 and 72 do not form a plurality ofpockets, each containing a cluster 90 of absorbent particulate polymermaterial 66 therebetween). In a certain embodiment, respective gridpatterns 92 of the first and second absorbent layer 60 and 62 may besubstantially the same.

In a certain embodiment as illustrated in FIGS. 1-8A, the amount ofabsorbent particulate polymer material 66 and 74 may vary along thewidth 116 of the grid pattern 92 substantially perpendicularly to thelongitudinal axis 36 of disposable absorbent diaper 10. In a certainembodiment, the grid pattern may be divided into absorbent zones 120 a,121 a and 122 a, or another number of zones, in which the amount ofabsorbent particulate polymer material 66 and 74 per unit area of theabsorbent core 14 varies from zone to zone. As used herein, “absorbentzone” refers to a region of the absorbent particulate polymer materialarea having boundaries that are perpendicular to the longitudinal axisshown in FIG. 8A. The amount of absorbent particulate polymer material66 and 74 may, in a certain embodiment, gradually transition from one ofthe plurality of absorbent zones 120 a, 121 a, and 122 a to another.This gradual transition in amount of absorbent particulate polymermaterial 66 and 74 may reduce the possibility of cracks forming in theabsorbent core 14.

In the embodiment illustrated in FIGS. 1-8A the first and second sideabsorbent zones 120 a and 122 are spaced from one another and extendsubstantially parallel to the longitudinal axis 36 of the diaper 10 andthe central absorbent zone 121 a extends substantially along thelongitudinal axis and between the first and second side absorbent zones120 a and 122 a. The absorbent particulate polymer material 66 and 74present in the first and second side absorbent zones 120 and 122 of theabsorbent core 14 has a basis weight greater than the basis weight ofthe absorbent particulate polymer material 66 and 74 present in thecentral absorbent zone 121 a of the absorbent core 14. According to acertain embodiment, the basis weight of the absorbent particulatepolymer material 66 and 74 present in the first and second sideabsorbent zones 120 a and 122 a of the absorbent core 14 is greater thanthe basis weight of the absorbent particulate polymer material 66 and 74in the central absorbent zone 121 a the absorbent core 14.

In the embodiment illustrated in FIGS. 1-8A, the absorbent particulatepolymer material 66 and 74 in the central absorbent zone 121 a of theabsorbent core 14 has a higher basis weight than in the first and secondside absorbent zones 120 a and 122 a of the absorbent core 14. When theabsorbent core 14 according to this embodiment is subjected to a flushof liquid directed at the central absorbent zone 121 a, liquid thatflows over and past the central absorbent zone 121 a contacts the sideabsorbent zones 120 a and 122 a. The first and second side absorbentzones 120 a and 122 a have more absorbent particulate polymer materialand have greater capacity to absorb such liquid and deter flow of theliquid beyond the side absorbent zones 120 and 122 to prevent leakage.

Although the embodiment illustrated in FIGS. 1-8A has only threeabsorbent zones 120, 121 a, and 122 a, the absorbent diaper 10 mayinclude any number of absorbent zones having varying basis weights ofabsorbent particulate polymer. Furthermore, in other embodiments, theabsorbent particulate polymer material 66 and 74 may be varied indifferent patterns such as by placing more absorbent particulate polymermaterial in the central absorbent zone 121 a than in the side absorbentzone 120 a and 122 a or alternating areas of greater and lesser amountsof absorbent particulate polymer material per unit area of the absorbentcore.

In FIG. 8A, the areas of greater absorbent particulate polymer materialbasis weight 120 a and 122 a are substantially parallel and continuousand the absorbent core 14 is substantially rectangular. In certainembodiments, areas of greater absorbent particulate polymer materialbasis weight may have other shapes such as curved or be intermittent, orboth. Furthermore, in certain embodiments, the absorbent core may havedifferent shapes including but not limited to hourglass, oval, round,square and triangular. FIG. 8B shows an embodiment comprising continuousareas of greater absorbent particulate polymer material basis weight 120b and 122 b curved inwardly so as to form a concave pattern and adjacentareas of lower absorbent particulate polymer material basis weight 121b. FIG. 8C shows an embodiment comprising continuous areas of greaterabsorbent particulate polymer material basis weight 120 c and 122 ccurved inwardly so as to form an hourglass pattern and a central area oflower absorbent particulate polymer material basis weight 121 c. FIG. 8Dshows an embodiment comprising continuous areas of greater absorbentparticulate polymer material basis weight 120 d and 122 d curvedoutwardly so as to form a convex pattern and adjacent areas of lowerabsorbent particulate polymer material basis weight 121 d. FIG. 8E showsan embodiment comprising substantially straight parallel areas ofgreater absorbent particulate polymer material basis weight 120 e and122 e and adjacent areas of lower absorbent particulate polymer materialbasis weight 121 e, the parallel areas of greater absorbent particulatepolymer material basis weight 120 e and 122 e having a length shorterthan that of the adjacent areas of lower absorbent particulate polymermaterial basis weight 121 e. FIG. 8F shows an embodiment comprisingsubstantially straight parallel intermittent areas of greater absorbentparticulate polymer material basis weight 120 f and 122 f and adjacentareas of lower absorbent particulate polymer material basis weight 121f.

Another embodiment of an absorbent core 14′ is illustrated in FIG. 9 andthe basis weight of the absorbent particulate polymer material 66 and 74varies across the absorbent core 14′ in a direction substantiallyparallel to the longitudinal axis 36. This absorbent core 14′ comprisesfirst and second end absorbent zones 123 and 124, spaced form oneanother and extending substantially perpendicular to the longitudinalaxis of the absorbent core, and a central absorbent zone 125, extendingsubstantially along the longitudinal axis 36 and between the first andsecond end absorbent zones 123 and 124. The basis weight of theabsorbent particulate polymer material in the absorbent end zones 123and 124 of the absorbent core 14′ is greater than in the centralabsorbent zone 125 of the absorbent core 14′. In this embodiment, thebasis weight of the absorbent particulate polymer material 66 and 74 inthe first and second end absorbent zones 123 and 124 of the absorbentcore 14′ is greater than the basis weight of the absorbent particulatepolymer material 66 and 74 in the central absorbent zone 125 of theabsorbent core 14′. When the absorbent core 14′ illustrated in FIG. 9 issubjected to a flush of liquid directed at the central absorbent zone125, liquid that flows past the central absorbent zone 125 encountersend absorbent zones 123 and 124 which have greater capacity to absorband hold such liquid.

Although the absorbent core 14′ illustrated in FIG. 9 has only threeabsorbent zones 123, 124, and 125, the absorbent core 14′ may includeany number of absorbent zones arranged in a variety of differentpatterns of varying absorbent particulate polymer material basisweights. In other embodiments, the basis weight of the absorbentparticulate polymer material 66 and 74 in the central absorbent zone 125may be greater than in the end absorbent zones 123 and 124 or theabsorbent core 14′ may include a multitude of alternating absorbentzones of varying absorbent particulate polymer material basis weights.

Another embodiment of an absorbent core 14″ is illustrated in FIG. 10and comprises first and second side absorbent zones 120′ and 122′ spacedfrom one another and extending substantially parallel to thelongitudinal axis 36, first and second end absorption zones 123′ and124′ spaced from one another and extending substantially perpendicularlyto the longitudinal axis 36, and a central portion 121′ and 125′extending substantially along the longitudinal axis 36 and between thefirst and second side absorbent zones 120′ and 122′ and between thefirst and second end absorbent zones 123′ and 124′. The basis weight ofthe absorbent particulate polymer material 66 and 74 in the first andsecond side portions 120′ and 122′ of the absorbent core 14″ is greaterthan the basis weight of the absorbent particulate polymer material 66and 74 in the central portion 121′ and 125′ of the absorbent core 14″and the basis weight of the absorbent particulate polymer material 66and 74 in the first and second end portions 123′ and 124′ of theabsorbent core 14″ is greater than the basis weight of the absorbentparticulate polymer material 66 and 74 in the central portion 121′ and125′ of the absorbent core 14″. When the absorbent core 14″ illustratedin FIG. 10 is subjected to a rush of liquid directed at the centralabsorbent zone 121′ and 125′, liquid that flows past the centralabsorbent zone 121′ and 125′ encounters and may be absorbed by the sideabsorbent zones 120′ and 122′ and the end absorbent zones 123′ and 124′which all have greater absorbent particulate polymer material basisweights. As with the other embodiments described hereinabove, it shouldbe understood that the absorbent particulate polymer material 66 and 74may be arranged in a variety of different patterns of varying absorbentparticulate polymer material basis weights. In one such embodiment, thecentral absorbent zone 121′ and 125′ may have a higher absorbentparticulate polymer material basis weight than the side absorbent zones120′ and 122′ and the end absorbent zones 123′ and 124′.

The amount of absorbent particulate polymer material 66 and 74 presentin the absorbent core 14 may vary, but in certain embodiments, ispresent in the absorbent core in an amount greater than about 80% byweight of the absorbent core, or greater than about 85% by weight of theabsorbent core, or greater than about 90% by weight of the absorbentcore, or greater than about 95% by weight of the core. In a particularembodiment, the absorbent core 14 consists essentially of the first andsecond substrates 64 and 72, the absorbent particulate polymer material66 and 74, and the thermoplastic adhesive composition 68 and 76. In anembodiment, the absorbent core 14 may be substantially cellulose free.

According to certain embodiments, the weight of absorbent particulatepolymer material 66 and 74 in at least one freely selected first squaremeasuring 1 cm×1 cm may be at least about 10%, or 20%, or 30%, 40% or50% higher than the weight of absorbent particulate polymer material 66and 74 in at least one freely selected second square measuring 1 cm×1cm. In a certain embodiment, the first and the second square arecentered about the longitudinal axis.

The absorbent particulate polymer material area, according to anexemplary embodiment, may have a relatively narrow width in the crotcharea of the absorbent article for increased wearing comfort. Hence, theabsorbent particulate polymer material area, according to an embodiment,may have a width as measured along a transverse line which is positionedat equal distance to the front edge and the rear edge of the absorbentarticle, which is less than about 100 mm, 90 mm, 80 mm, 70 mm, 60 mm oreven less than about 50 mm.

It has been found that, for most absorbent articles such as diapers, theliquid discharge occurs predominately in the front half of the diaper.The front half of the absorbent core 14 should therefore comprise mostof the absorbent capacity of the core. Thus, according to certainembodiments, the front half of said absorbent core 14 may comprise morethan about 60% of the superabsorbent material, or more than about 65%,70%, 75%, 80%, 85%, or 90% of the superabsorbent material.

In certain embodiments, the absorbent core 14 may further comprise anyabsorbent material that is generally compressible, conformable,non-irritating to the wearer's skin, and capable of absorbing andretaining liquids such as urine and other certain body exudates. In suchembodiments, the absorbent core 14 may comprise a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp, which is generallyreferred to as airfelt, creped cellulose wadding, melt blown polymers,including co-form, chemically stiffened, modified or cross-linkedcellulosic fibers, tissue, including tissue wraps and tissue laminates,absorbent foams, absorbent sponges, or any other known absorbentmaterial or combinations of materials. The absorbent core 14 may furthercomprise minor amounts (typically less than about 10%) of materials,such as adhesives, waxes, oils and the like.

Exemplary absorbent structures for use as the absorbent assemblies aredescribed in U.S. Pat. No. 4,610,678 (Weisman et al.); U.S. Pat. No.4,834,735 (Alemany et al.); U.S. Pat. No. 4,888,231 (Angstadt); U.S.Pat. No. 5,260,345 (DesMarais et al.); U.S. Pat. No. 5,387,207 (Dyer etal.); U.S. Pat. No. 5,397,316 (LaVon et al.); and U.S. Pat. No.5,625,222 (DesMarais et al.).

In a certain embodiment best illustrated in FIG. 2, the elasticized legcuffs 24 may comprise absorbent particulate polymer material 126 whichmay be laid down directly of the elasticized legs cuffs 24 in the samemanner as the absorbent particulate polymer material 66 is laid down onfirst substrate 64 (described below) or may be formed on a separatesubstrate and added later.

The thermoplastic adhesive material 68 and 76 may serve to cover and atleast partially immobilize the absorbent particulate polymer material 66and 74. In one embodiment of the present invention, the thermoplasticadhesive material 68 and 76 can be disposed essentially uniformly withinthe absorbent particulate polymer material 66 and 74, between thepolymers. However, in a certain embodiment, the thermoplastic adhesivematerial 68 and 76 may be provided as a fibrous layer which is at leastpartially in contact with the absorbent particulate polymer material 66and 74 and partially in contact with the substrate layers 64 and 72 ofthe first and second absorbent layers 60 and 62. FIGS. 3, 4, and 7 showsuch a structure, and in that structure, the absorbent particulatepolymer material 66 and 74 is provided as a discontinuous layer, and alayer of fibrous thermoplastic adhesive material 68 and 76 is laid downonto the layer of absorbent particulate polymer material 66 and 74, suchthat the thermoplastic adhesive material 68 and 76 is in direct contactwith the absorbent particulate polymer material 66 and 74, but also indirect contact with the second surfaces 80 and 84 of the substrates 64and 72, where the substrates are not covered by the absorbentparticulate polymer material 66 and 74. This imparts an essentiallythree-dimensional structure to the fibrous layer of thermoplasticadhesive material 68 and 76, which in itself is essentially atwo-dimensional structure of relatively small thickness, as compared tothe dimension in length and width directions. In other words, thethermoplastic adhesive material 68 and 76 undulates between theabsorbent particulate polymer material 68 and 76 and the second surfacesof the substrates 64 and 72.

Thereby, the thermoplastic adhesive material 68 and 76 may providecavities to cover the absorbent particulate polymer material 66 and 74,and thereby immobilizes this material. In a further aspect, thethermoplastic adhesive material 68 and 76 bonds to the substrates 64 and72 and thus affixes the absorbent particulate polymer material 66 and 74to the substrates 64 and 72. Thus, in accordance with certainembodiments, the thermoplastic adhesive material 68 and 76 immobilizesthe absorbent particulate polymer material 66 and 74 when wet, such thatthe absorbent core 14 achieves an absorbent particulate polymer materialloss of no more than about 70%, 60%, 50%, 40%, 30%, 20%, 10% accordingto the Wet Immobilization Test described herein. Some thermoplasticadhesive materials will also penetrate into both the absorbentparticulate polymer material 66 and 74 and the substrates 64 and 72,thus providing for further immobilization and affixation. Of course,while the thermoplastic adhesive materials disclosed herein provide amuch improved wet immobilization (i.e., immobilization of absorbentmaterial when the article is wet or at least partially loaded), thesethermoplastic adhesive materials may also provide a very goodimmobilization of absorbent material when the absorbent core 14 is dry.The thermoplastic adhesive material 68 and 76 may also be referred to asa hot melt adhesive.

Without wishing to be bound by theory, it has been found that thosethermoplastic adhesive materials which are most useful for immobilizingthe absorbent particulate polymer material 66 and 74 combine goodcohesion and good adhesion behavior. Good adhesion may promote goodcontact between the thermoplastic adhesive material 68 and 76 and theabsorbent particulate polymer material 66 and 74 and the substrates 64and 72. Good cohesion reduces the likelihood that the adhesive breaks,in particular in response to external forces, and namely in response tostrain. When the absorbent core 14 absorbs liquid, the absorbentparticulate polymer material 66 and 74 swells and subjects thethermoplastic adhesive material 68 and 76 to external forces. In certainembodiments, the thermoplastic adhesive material 68 and 76 may allow forsuch swelling, without breaking and without imparting too manycompressive forces, which would restrain the absorbent particulatepolymer material 66 and 74 from swelling.

In accordance with certain embodiments, the thermoplastic adhesivematerial 68 and 76 may comprise, in its entirety, a single thermoplasticpolymer or a blend of thermoplastic polymers, having a softening point,as determined by the ASTM Method D-36-95 “Ring and Ball”, in the rangebetween 50° C. and 300° C., or alternatively the thermoplastic adhesivematerial may be a hot melt adhesive comprising at least onethermoplastic polymer in combination with other thermoplastic diluentssuch as tackifying resins, plasticizers and additives such asantioxidants. In certain embodiments, the thermoplastic polymer hastypically a molecular weight (Mw) of more than 10,000 and a glasstransition temperature (Tg) usually below room temperature or −6°C.>Tg<16° C. In certain embodiments, typical concentrations of thepolymer in a hot melt are in the range of about 20 to about 40% byweight. In certain embodiments, thermoplastic polymers may be waterinsensitive. Exemplary polymers are (styrenic) block copolymersincluding A-B-A triblock structures, A-B diblock structures and (A-B)nradial block copolymer structures wherein the A blocks arenon-elastomeric polymer blocks, typically comprising polystyrene, andthe B blocks are unsaturated conjugated diene or (partly) hydrogenatedversions of such. The B block is typically isoprene, butadiene,ethylene/butylene (hydrogenated butadiene), ethylene/propylene(hydrogenated isoprene), and mixtures thereof.

Other suitable thermoplastic polymers that may be employed aremetallocene polyolefins, which are ethylene polymers prepared usingsingle-site or metallocene catalysts. Therein, at least one comonomercan be polymerized with ethylene to make a copolymer, terpolymer orhigher order polymer. Also applicable are amorphous polyolefins oramorphous polyalphaolefins (APAO) which are homopolymers, copolymers orterpolymers of C2 to C8 alpha olefins.

In exemplary embodiments, the tackifying resin has typically a Mw below5,000 and a Tg usually above room temperature, typical concentrations ofthe resin in a hot melt are in the range of about 30 to about 60%, andthe plasticizer has a low Mw of typically less than 1,000 and a Tg belowroom temperature, with a typical concentration of about 0 to about 15%.

In certain embodiments, the thermoplastic adhesive material 68 and 76 ispresent in the form of fibers. In some embodiments, the fibers will havean average thickness of about 1 to about 50 micrometers or about 1 toabout 35 micrometers and an average length of about 5 mm to about 50 mmor about 5 mm to about 30 mm. To improve the adhesion of thethermoplastic adhesive material 68 and 76 to the substrates 64 and 72 orto any other layer, in particular any other non-woven layer, such layersmay be pre-treated with an auxiliary adhesive.

In certain embodiments, the thermoplastic adhesive material 68 and 76will meet at least one, or several, or all of the following parameters:

An exemplary thermoplastic adhesive material 68 and 76 may have astorage modulus G′ measured at 20° C. of at least 30,000 Pa and lessthan 300,000 Pa, or less than 200,000 Pa, or between 140,000 Pa and200,000 Pa, or less than 100,000 Pa. In a further aspect, the storagemodulus G′ measured at 35° C. may be greater than 80,000 Pa. In afurther aspect, the storage modulus G′ measured at 60° C. may be lessthan 300,000 Pa and more than 18,000 Pa, or more than 24,000 Pa, or morethan 30,000 Pa, or more than 90,000 Pa. In a further aspect, the storagemodulus G′ measured at 90° C. may be less than 200,000 Pa and more than10,000 Pa, or more than 20,000 Pa, or more then 30,000 Pa. The storagemodulus measured at 60° C. and 90° C. may be a measure for the formstability of the thermoplastic adhesive material at elevated ambienttemperatures. This value is particularly important if the absorbentproduct is used in a hot climate where the thermoplastic adhesivematerial would lose its integrity if the storage modulus G′ at 60° C.and 90° C. is not sufficiently high.

G′ is measured using a rheometer as schematically shown in FIG. 9 forthe purpose of general illustration only. The rheometer 127 is capableof applying a shear stress to the adhesive and measuring the resultingstrain (shear deformation) response at constant temperature. Theadhesive is placed between a Peltier-element acting as lower, fixedplate 128 and an upper plate 129 with a radius R of e.g., 10 mm, whichis connected to the drive shaft of a motor to generate the shear stress.The gap between both plates has a height H of e.g., 1500 micron. ThePeltier-element enables temperature control of the material (+0.5° C.).The strain rate and frequency should be chosen such that allmeasurements are made in the linear viscoelastic region.

The absorbent core 14 may also comprise an auxiliary adhesive layer 69.The auxiliary adhesive may be deposited on the first and secondsubstrates 64 and 72 of the respective first and second absorbent layers60 and 62 before application of the absorbent particulate polymermaterial 66 and 74 for enhancing adhesion of the absorbent particulatepolymer materials 66 and 74 and the thermoplastic adhesive material 68and 76 to the respective substrates 64 and 72. The auxiliary glue 69 mayalso aid in immobilizing the absorbent particulate polymer material 66and 74 and may comprise the same thermoplastic adhesive material asdescribed hereinabove or may also comprise other adhesives including butnot limited to sprayable hot melt adhesives, such as H.B. Fuller Co.(St. Paul, Minn.) Product No. HL-1620-B. The auxiliary glue may beapplied to the substrates 64 and 72 by any suitable means, but accordingto certain embodiments, may be applied in about 0.5 to about 1 mm wideslots spaced about 0.5 to about 2 mm apart.

The cover layer 70 shown in FIG. 4 may comprise the same material as thesubstrates 64 and 72, or may comprise a different material. In certainembodiments, suitable materials for the cover layer 70 are the non-wovenmaterials, typically the materials described above as useful for thesubstrates 64 and 72.

Method and Apparatus for Making Absorbent Articles

A printing system 130 for making an absorbent core 14 in accordance withan embodiment of this invention is illustrated in FIG. 12 and maygenerally comprise a first printing unit 132 for forming the firstabsorbent layer 60 of the absorbent core 14 and a second printing unit134 for forming the second absorbent layer 62 of the absorbent core 14.

The first printing unit 132 may comprise a first auxiliary adhesiveapplicator 136 for applying an auxiliary adhesive 69 to the substrate64, which may be a nonwoven web, a first rotatable support roll 140 forreceiving the substrate 64, a hopper 142 for holding absorbentparticulate polymer material 66, a printing roll 144 for transferringthe absorbent particulate polymer material 66 to the substrate 64, and athermoplastic adhesive material applicator 146 for applying thethermoplastic adhesive material 68 to the substrate 64 and the absorbentparticulate polymer 66 material thereon.

The second printing unit 134 may comprise a second auxiliary adhesiveapplicator 148 for applying an auxiliary adhesive 73 to the secondsubstrate 72, a second rotatable support roll 152 for receiving thesecond substrate 72, a second hopper 154 for holding the absorbentparticulate polymer material 74, a second printing roll 156 fortransferring the absorbent particulate polymer material 74 from thehopper 154 to the second substrate 72, and a second thermoplasticadhesive material applicator 158 for applying the thermoplastic adhesivematerial 76 to the second substrate 72 and the absorbent particulatepolymer material 74 thereon.

The printing system 130 also includes a guide roller 160 for guiding theformed absorbent core from a nip 162 between the first and secondrotatable support rolls 140 and 152.

The first and second auxiliary applicators 136 and 148 and the first andsecond thermoplastic adhesive material applicators 146 and 158 may be anozzle system which can provide a relatively thin but wide curtain ofthermoplastic adhesive material.

Turning to FIG. 13, portions of the first hopper 142, first support roll140, and first printing roll 144 are illustrated. As also shown in FIG.16, the first rotatable support roll 140, which has the same structureas the second rotatable support roll 152, comprises a rotatable drum 164and a peripheral vented support grid 166 for receiving the firstsubstrate 64.

As also illustrated in FIG. 14, the first printing roll 144, which hasthe same structure as the second printing roll 156, comprises arotatable drum 168 and a plurality of absorbent particulate polymermaterial reservoirs 170 and 171 in a peripheral surface 172 of the drum168. The reservoirs 170 and 171, best illustrated in FIG. 15, may have avariety of shapes, including cylindrical, conical, or any other shape.The reservoirs 170 and 171 may lead to an air passage 174 in the drum168 and comprise a vented cover 176 for holding adhesive particulatepolymer material 66 in the reservoir and preventing the adhesiveparticulate polymer material 66 from falling or being pulled into theair passage 174.

The first printing roll 144 is designed to produce a certain embodimentlike the absorbent core 14 illustrated in FIG. 5 wherein side absorbentzones 120 and 122 have a higher basis weight of absorbing particulatepolymer material 66 and 74 than the central absorbent zone 121. In theembodiment illustrated in FIG. 14, this effect may be achieved by havinga corresponding set of reservoirs 170 which are relatively deep and asecond set 171 of reservoirs which are relatively shallow, such that thedeeper reservoirs 170 carry more absorbent particulate polymer materialand deliver more absorbent particulate polymer material 66 to the sideabsorbent zones 120 and 122 and the more shallow reservoirs 171 holdless adhesive particulate polymer material and deliver less absorbentparticulate polymer material 66 to the central zone 121 of the absorbentcore 14. The sets of deeper and shallower reservoirs 170 and 171, ofcourse, can be arranged in any variety of patterns or configurations tocreate an absorbent core 14 with any corresponding variety of varyingabsorbent particulate polymer material basis weights across theabsorbent core 14. FIG. 15, in particular, illustrates the difference involumetric sizes of first and second sets of reservoirs 170 and 171.

Other methods of delivering a varying profile of absorbent particulatepolymer basis weights to the absorbent core 14 includes, but is notlimited to, applying a higher vacuum in sections of the first and secondrotatable support rolls 140 and 152 where more absorbent particulatepolymer material is desired or, when the absorbent particulate polymermaterial is delivered to the absorbent core substrate 64 pneumatically,such as when combining cellulosic fibers with absorbent particulatepolymer material, directing the air stream carrying the absorbentparticulate polymer material and cellulosic fibers to areas of theabsorbent core substrate where a higher basis weight of absorbentparticulate polymer material is desired.

In operation, the printing system 130 receives the first and secondsubstrate 64 and 72 into the first and second printing units 132 and134, respectively, the first substrate 64 is drawn by the rotating firstsupport roll 140 past the first auxiliary adhesive applicator 136 whichapplies the first auxiliary adhesive to the first substrate 64 in apattern such as described hereinabove. A vacuum (not shown) within thefirst support roll 140 draws the first substrate 64 against the verticalsupport grid 166 and holds the first substrate 64 against the firstsupport roll 140. This presents an uneven surface on the first substrate64. Due to gravity, or by using the vacuum means, the substrate 64 willfollow the contours of the uneven surface and thereby the substrate 64will assume a mountain and valley shape. The absorbent particulatepolymer material 66 may accumulate in the valleys presented by thesubstrate 64. The first support roll 140 then carries the firstsubstrate 64 past the rotating first printing roll 144 which transfersthe absorbent particulate polymer material 66 from the first hopper 142to the first substrate 64 in the grid pattern 92 which is bestillustrated in FIGS. 5 and 6. A vacuum (not shown) in the first printingroll 144 may hold the absorbent particulate polymer material 66 in thereservoirs 170 until time to deliver the absorbent particulate polymermaterial 66 to the first substrate 64. The vacuum may then be releasedor air flow through the air passages 174 may be reversed to eject theabsorbent particulate polymer material 66 from the reservoirs and ontothe first substrate 64. The absorbent particulate polymer material 66may accumulate in the valleys presented by the substrate 64. The supportroll 140 then carries the printed first substrate 64 past thethermoplastic adhesive material applicator 136 which applies thethermoplastic adhesive material 68 to cover the absorbent particulatepolymer material 66 on the first substrate 64.

Hence, the uneven surface of the vented support grid 166 of the supportrolls 140 and 152 determines the distribution of absorbent particulatepolymeric material 66 and 74 throughout the absorbent core 14 andlikewise determines the pattern of junction areas 96.

Meanwhile, the second rotatable support roll draws the second substrate72 past the second auxiliary adhesive applicator 148 which applies anauxiliary adhesive to the second substrate 72 in a pattern such as isdescribed hereinabove. The second rotatable support roll 152 thencarries the second substrate 72 past the second printing roll 156 whichtransfers the absorbent particulate polymer material 74 from the secondhopper 154 to the second substrate 72 and deposits the absorbentparticulate polymer material 74 in the grid pattern 92 on the secondsubstrate 72 in the same manner as described with regard to the firstprinting unit 132 above. The second thermoplastic adhesive materialapplicator 158 then applies the thermoplastic adhesive material 76 tocover the absorbent particulate polymer material 74 on the secondsubstrate 72. The printed first and second substrates 64 and 72 thenpass through the nip 162 between the first and second support rolls 140and 152 for compressing the first absorbent layer 60 and secondabsorbent layer 62 together to form the absorbent core 14.

In an optional further process step a cover layer 70 may be placed uponthe substrates 64 and 72, the absorbent particulate polymer material 66and 74, and the thermoplastic adhesive material 68 and 76. In anotherembodiment, the cover layer 70 and the respective substrate 64 and 72may be provided from a unitary sheet of material. The placing of thecover layer 70 onto the respective substrate 64 and 72 may then involvethe folding of the unitary piece of material.

FIGS. 17-19 illustrate certain embodiments of printing rolls 144′ and144″ for making corresponding embodiments of absorbent cores 14′ and 14″illustrated in FIGS. 9 and 10, respectively. As shown in FIGS. 17 and18, the printing roll 144′ for making the absorbent core 14′ illustratedin FIG. 9 comprises sets of deeper and shallower reservoirs 170′ and171′ for forming the end absorbent zones 123 and 124, which have ahigher absorbent particulate polymer material basis weight, and thecentral absorbent zone 125, which has a lower absorbent particulatepolymer material basis weight, respectively. Likewise, the printing roll144″ has sets of deeper and shallower reservoirs 170″ and 171″,respectively, for forming the side absorbent zones 120′ and 122′ and endabsorbent zones 123′ and 124′, having a higher basis weight of absorbentparticulate polymer material, and the central zone 121′ and 125′ havinga lower basis weight of absorbent particulate polymer material.

Absorbent articles such as the diapers 10 made in accordance withembodiments of this invention may be folded and packaged fordistribution and sale. Absorbent articles are typically bi-folded, butmay also be tri-folded. After folding, the folded absorbent articles maybe stacked to form a stack comprising a plurality of absorbent articles.The stack may then be compressed and encased in a packaging materialsuch as a bag, a pouch, a box, or the like.

All patents and patent applications (including any patents which issuethereon) assigned to the Procter & Gamble Company referred to herein arehereby incorporated by reference to the extent that it is consistentherewith.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A disposable absorbent article comprising: a chassis including atopsheet and a backsheet; and an absorbent core located between thetopsheet and the backsheet and comprising absorbent particulate polymermaterial, the disposable absorbent article having a longitudinal axisextending from a first end to a second end and the absorbent particulatepolymer material present in the absorbent core has a basis weight thatvaries across the absorbent core in a direction substantiallyperpendicular to the longitudinal axis or in a direction substantiallyparallel to the longitudinal axis.
 2. The disposable absorbent articleof claim 1, wherein the absorbent core is substantially cellulose free.3. The disposable absorbent article of claim 1, wherein the basis weightof the absorbent particulate polymer material varies across theabsorbent core in a direction substantially perpendicular to thelongitudinal axis, the absorbent core comprises first and second sideabsorbent zones spaced from one another and extending substantiallyparallel to the longitudinal axis and a central absorbent zone extendingalong the longitudinal axis and between the first and second sideabsorbent zones, the absorbent particulate polymer material in the firstand second side absorbent zones of the absorbent core has a basisweight, the absorbent particulate polymer material in the centralabsorbent zone of the absorbent core has a basis weight, and the basisweight of the absorbent particulate polymer material in the first andsecond side absorbent zones is greater than the basis weight of theabsorbent particulate polymer material in the central absorbent zone. 4.The disposable absorbent article of claim 1, wherein the absorbentparticulate polymer material varies across the absorbent core in adirection substantially parallel to the longitudinal axis, the absorbentcore comprises first and second end absorbent zones spaced from oneanother and extending substantially perpendicular to the longitudinalaxis and a central absorbent zone extending along the longitudinal axisand between the first and second end absorbent zones, the absorbentparticulate polymer material in the first and second end absorbent zonesof the absorbent core has a basis weight, the absorbent particulatepolymer material in the central absorbent zone of the absorbent core hasa basis weight, and the basis weight of the absorbent particulatepolymer material in the first and second end absorbent zones is greaterthan the basis weight of the absorbent particulate polymer material inthe central absorbent zone.
 5. The disposable absorbent article of claim1, wherein the basis weight of the absorbent particulate polymermaterial varies across the absorbent core in a direction substantiallyperpendicular to the longitudinal axis and in a direction substantiallyparallel to the longitudinal axis.
 6. The disposable absorbent articleof claim 5, wherein the absorbent core comprises first and second sideportions spaced from one another and extending substantially parallel tothe longitudinal axis, the absorbent core comprises first and second endportions spaced from one another and extending substantiallyperpendicular to the longitudinal axis, the absorbent core comprises acentral portion extending along the longitudinal axis and between thefirst and second side portions and between the first and second endportions, the absorbent particulate polymer material is present in thefirst and second side portions in an amount per unit area of theabsorbent core greater than an amount the absorbent particulate polymermaterial is present in the central portion per unit area of theabsorbent core, the absorbent particulate polymer material in the firstand second side absorbent zones of the absorbent core has a basisweight, the absorbent particulate polymer material in the first andsecond end absorbent zones of the absorbent core has a basis weight, theabsorbent particulate polymer material in the central absorbent zone ofthe absorbent core has a basis weight, the basis weight of the absorbentparticulate polymer material in the first and second side absorbentzones is greater than the basis weight of the absorbent particulatepolymer material in the central absorbent zone, and the basis weight ofthe absorbent particulate polymer material in the first and second endabsorbent zones is greater than the basis weight of the absorbentparticulate polymer material in the central absorbent zone.
 7. Thedisposable absorbent article of claim 1, wherein the disposableabsorbent article further comprises first and second cuffs extendingfrom the chassis proximate respective longitudinal edges of the chassis,the first and second cuffs comprising absorbent particulate polymermaterial.
 8. The disposable absorbent article of claim 1, wherein thedisposable absorbent article is a diaper or a pant.
 9. A method formaking an absorbent core for use in a disposable absorbent articlecomprising depositing an absorbent particulate polymer material on asubstrate to form an absorbent core having a longitudinal axis extendingfrom a first end to a second end such that the absorbent particulatepolymer material present in the absorbent core has a basis weight thatvaries across the absorbent core in a direction substantiallyperpendicular to the longitudinal axis or in a direction substantiallyparallel to the longitudinal axis.
 10. The method as in claim 9 whereinthe step of depositing comprises placing the substrate on a porousforming surface and depositing the absorbent particulate polymermaterial to the substrate while applying a vacuum to the substratethrough the porous forming surface.
 11. The method as in claim 10wherein the forming surface has recesses for receiving the substrate andthe absorbent particulate polymer material and the recesses are sizedand arranged to vary the basis weight of the absorbent particulatepolymer material across the substrate.
 12. The method as in claim 10wherein the vacuum applied to the substrate varies across the formingsurface so as to vary the basis weight of the absorbent particulatepolymer material across the substrate.
 13. The method as in claim 10wherein the step of depositing further comprises pneumaticallydelivering the absorbent particulate polymer material to the substrateand varying the pneumatic delivery to the forming surface so as to varythe amount of absorbent particulate polymer material across thesubstrate.
 14. A method for making a disposable absorbent articlecomprising: depositing an absorbent particulate polymer material on asubstrate to form an absorbent core; and locating the absorbent corebetween a topsheet and a backsheet of a chassis, wherein the disposableabsorbent article has a longitudinal axis extending from a first end toa second end and the step of depositing the absorbent particulatepolymer comprises varying the deposition of the absorbent particulatepolymer such that the absorbent particulate polymer material present inthe absorbent core has a basis weight that varies across the absorbentcore in a direction substantially perpendicular to the longitudinal axisor in a direction substantially parallel to the longitudinal axis.